Nr

these measures can be adjusted if experimental data are available to support alternative performance ranges.

Nonstructural performance levels include the performance of components such as elevators, piping, fire sprinkler systems, and heating, ventilation, and air conditioning (HVAC) equipment and building contents such as computers, bookshelves, and art objects. Nonstructural performance levels can be defined as follows:

• Operational performance level requires the postearthquake damage state of all nonstructural elements to remain functional and in operation.

• IO performance level allows for minor disruption due to shifting and damage of components, but all nonstructural components are generally in place and functional.

• LS performance level allows for damage to components but does not include failure of items heavy enough to pose a risk of severe injuries or secondary hazards from damage to high-pressure toxic and fire-suppressing piping.

• Reduced hazard is a postearthquake damage state that considers risk to groups of people from falling heavy objects such as cladding and heavy ceilings.

• Finally, it is also possible to include what is called a ''not considered'' performance level. This performance level is provided to cover those nonstructural elements that have not been evaluated as having an impact on the overall structural response. In fact, it is common for computer models evaluating seismic demands to ignore the presence of nonstructural elements.

When structural and nonstructural performance levels are combined, the resulting building performance level is established. Table 21.1 shows how such a performance level is determined. Note that only a few selected performance levels are displayed in Table 21.1. In the context of Table 21.1, if a building performance level of III-C were selected, this would require LS performance level at both structural and nonstructural elements.